Grease regularly and they will last indefinitely providing grease is getting to the bushes and not exuding through the Welsh washers at the top and bottom of king pin assembly. Always seal these with varnish or paint after renewing bushes.
Any of the Imp specialists sells a kit with new washers, sealing rings, and bushings.
Make sure you state you want bushes with grease holes in them, (king pin kits do not always have bushes with the holes). The kits should be complete: king pin D, bolt, nut and ring C, two metal dust caps E, two metal rings I and J, two rubber seal rings H.
See this month's Impressions - Jan. 1996 about stainless steel kingpins.
Written and send by Bert Clewits
The Noble Kingpin / by Eric Barter. - Impressions 1990, June. - p. 51-52
If the king-pins are stuck - what do you do:
Most manuals state that the stub axle / king-pin set-up is removed from the wishbone and then you remove the pin. If a vice is not availbale, it's often better to remove the pin insitu. Remove grease nipples, hub, back plate, cotter-pin, track-rod end and top welsh washer. Cotter-pins are removed by unscrewing the nut still a few threads show past flush, and then bolting the pin through with a large hammer. It is advisable to support the end of the wishbone with a large wooden block while you are belting the king-pin. Some king-pins will not budge however hard you hit them - you may well have to them the assembly to an engineering shop to have them pressed out. (nut then removed.) Welch plug removed by spearing with a sharp chisel. A drift is then placed on the pin and a very large club hammer will then drive out the pin and bottom welch plug. The bushes will drift out using a 9/16" bolt head (downwards). New bushes are best pushed up until flush by a G-clamp, protect the bush with a small piece of wood - ensuring that the grease holes align.
It is advisable to support the end of the wishbone with a large wooden block while you are belting the king-pin. Some king-pins will not budge however hard you hit them - you may well have to them the assembly to an engineering shop to have them pressed out.
When confronted with king pins that have part-siezed, but not actually worn out (i.e. lack of greasing), get an assistant to turn the steering wheel while you keep steady pressure on the grease gun. Often grease will gradually work its way in.
Too much pressure can blow out the welch washers.
Re-grease at least every six months.
Nigel Lenton. - Impressions 2 (1982), 9 (Oct.). - p. 6
Date: Tue, 7 Sep 1999 16:54:06 -0400
From: David Oakes
Subject: [imps] Front Suspension
>I have new king pins to fit, but don't know how to remove the old PTFE
>washers, do I need a special tool, I'm worried about doing damage.
King Pins! Welcome to the most frustrating service job on the Imp! I suspect you are refering to the Welch washers - the caps that sit on top of and at the bottom of the king pin/stub axle assembly? If you are then the way to remove them is a cold chisel and large hammer. Don't listen to the Haynes Manual bollocks of 'Collapse the domed welch washers with light hammer blows'. What was that bloke drinking? Dig in the edge of the cold chisle and hammer it side ways on to the welch washer. You may get lucky and it will pop out. I've always found I have to resort to drilling lots of holes in the Welch washer until you can pick it out with a screw driver. It doesn't matter that you are likely to drill into the top of the king pin because if you're taking it apart you'll be replacing that anyway. Ditto for the Welch washers.
The PTFE washers you just pick off with a screw driver (if they don't fall off) once the king pin has been driven out.
That's the easy bit. Now for putting it all back together again. Oh, you'll have hours of fun with that!
From: Gary Henderson
Date: Wed, 8 Sep 1999 09:30:34 +1200
Subject: Re: [imps] Front Suspension
Hi David, Derek & all
To extract the welch plugs: Drill a hole in the middle (say 7/64") and run in a self-tapping screw.. When it bottoms on the end of the king-pin, it'll push the welch-plug out; otherwise you can use it as a handle to rack the welch-plug loose.
By the way, it's definitely much easier to remove the entire stub-axle assembly from the car and take it to the nearest big vise to play with. (If I remember rightly, you can remove the brake backing-plate without undoing hydraulic connections and leave it hanging from a wire hook on the car - it's been a while now so I'm not 100% sure on this point.)
Before starting any of this, apply penetrating-oil to the cotter-pin - it needs time to do its work!
When reassembling, apply anti-seize to the cotter-pin and its immediate neighbourhood in the king-pin carrier, so it'll come out easier in 2010.
No special tools needed, but you'll need a drill-press or similar to shove the bushes in. (Or else a lash-up of bolt, nut & assorted washers.)
Suspension, dampers and steering